From: Tejun Heo <tj@kernel.org>
To: Li Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Cgroups <cgroups@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 1/6] cgroup: initialize cgrp->dentry before css_alloc()
Date: Wed, 23 Jan 2013 08:35:36 -0800 [thread overview]
Message-ID: <20130123163536.GA2373@mtj.dyndns.org> (raw)
In-Reply-To: <50FF4C4D.4020405@huawei.com>
Hello, Li.
On Wed, Jan 23, 2013 at 10:34:53AM +0800, Li Zefan wrote:
> Scheduler changes made in patch #2 are preparation for #3 and #4.
>
> - for #3:
>
> After ss->css_alloc(), there's a small window that tg->css.cgroup is NULL.
> With the change, tg won't be seen before ss->css_online(), so the scheduler
> won't see NULL tg->css.cgroup.
>
> - for #4:
>
> If tg is unregistered and removed from global list in css_free(), and if
> we kfree cgroup right after ss->css_free(), the scheduler can access
> invalid tg->css.cgroup, because tg is also protected by RCU.
Can you please incorporate the above into the patch descriptions?
Thanks!
--
tejun
prev parent reply other threads:[~2013-01-23 16:35 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-17 8:03 [PATCH 1/6] cgroup: initialize cgrp->dentry before css_alloc() Li Zefan
2013-01-17 8:03 ` [PATCH 2/6] sched: split out tg creation/destruction to css_online/css_offline Li Zefan
2013-01-17 8:03 ` [PATCH 3/6] sched: remove redundant NULL cgroup check in task_group_path() Li Zefan
2013-01-17 8:04 ` [PATCH 4/6] cgroup: remove duplicate RCU free on struct cgroup Li Zefan
2013-01-17 8:04 ` [PATCH 5/6] cgroup: remove synchronize_rcu() from cgroup_diput() Li Zefan
2013-01-17 8:05 ` [PATCH 6/6] cgroup: remove bogus comments in cgroup_diput() Li Zefan
2013-01-23 0:27 ` [PATCH 1/6] cgroup: initialize cgrp->dentry before css_alloc() Tejun Heo
2013-01-23 0:35 ` Andrew Morton
2013-01-23 2:34 ` Li Zefan
2013-01-23 16:35 ` Tejun Heo [this message]
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